DESCRIPTION (Adapted from applicant's description): Research has recently documented that behaviors such as self-comforting (e.g., thumb sucking) and gaze aversion during frustrating situations lead to subsequent reductions in negative affect in infants as young as 4- and 5-months of age. What is less well known, however, are the factors associated with individual differences in emotion regulation. That is, there is a range of abilities in emotion regulation and what accounts for such variability is still relatively unknown. It is proposed that the development of emotion regulation is complex and involves multiple systems within the infant and his/her environment. Thus, factors such as the child's gender, temperament, cognitive, emerging language development, the developing internal working model of the attachment relationship with their mother and father, parent sensitivity, and familial conditions (e.g., marital conflict) may all play a part in the development of emotion regulation. Furthermore, it is proposed that variation in emotion regulation, even during infancy, will predict later social competence, (e.g., self-control), the ability to comply with adult requests, as well as self-assertive behaviors. The father is also included in this study because recent research is showing that the fathers' role may differ from the mothers during infancy; fathers may be particularly salient in children's development of regulation skills. The study will be longitudinal in which infants and parents will be observed in a laboratory setting when infants are 3, 5, 7, 12, 14, and 20 months of age. The first three visits will center on infants' affective and regulatory responses during the Still-Face Paradigm as well as mothers' and fathers' sensitivity in responding to their infants' emotionality. Attachment data will be collected at the 12 (infant-mother) and 14 month (infant-father) visits. Finally, measures of children's social competence during several laboratory paradigms as well as mothers' and fathers' control tactics will be assessed at the 20 month visit. Questionnaire data at appropriate ages also will be obtained from mothers and fathers to assess parents' perceptions of their child's temperament, language development, parental involvement, and marital conflict. In sum, four goals guide this study: (1) To examine the correlates and predictors of affect regulation from infancy to toddlerhood. (2) To examine the degree to which emotion regulatory patterns during early infancy are predictive of infant-parent attachment and to what extent such relations are mediated or moderated by parent sensitivity. (3) To examine the extent to which emotion regulatory patterns and attachment during infancy predict later styles of emotion regulation and social competence during toddlerhood. (4) With respect to the above-mentioned questions, to compare processes occurring for infant-mother dyads versus infant-father dyads.